Well kill

Abstract: A conventional well bore drilling system includes a coiled tubing mounted on a reel and connected to a mud supply for supplying mud through the tubing to a downhole end of the tubing to which is attached the downhole drilling tool. The system is modified by the addition of an inner tubing attached to the reel shaft and extending through the outer tubing to the drilling tool. The drilling mud is supplied in the space between the inner and outer tubes and a gas is supplied through the inner tube, The gas is vented through a coupling at the drilling tool into the well bore so as to enter the well bore and reduce the hydrostatic head of the fluids within the well bore to an under balanced condition below the pressure of the producing zone. As the gas is supplied through the inner tube, it is maintained separate from the liquid outside the inner tube and accordingly can be by passed into the well bore without entering the downhole MWD or motor drive systems and in addition the mud pulses generated by the downhole MWD system can be communicated through the drilling mud in conventional manner without losses due to gas within the liquid.

Abstract: Methods and systems are provided for maintaining fluid pressure control of a well bore 30 drilled through a subterranean formation using a drilling rig 25 and a drill string 50, whereby a kick may be circulated out of the well bore and/or a kill fluid may be circulated into the well bore, at a kill rate that may be varied. A programmable controller 100 may be included to control execution of a circulation/kill procedure whereby a mud pump 90 and/or a well bore choke 70 may be regulated by the controller. One or more sensors may be interconnected with the controller to sense well bore pressure conditions and/or pumping conditions. Statistical process control techniques may also be employed to enhance process control by the controller. The controller 100 may further execute routine determinations of circulating kill pressures at selected kill rates. The controller may control components utilized in the circulation/kill procedure so as to maintain a substantially constant bottom hole pressure on the formation while executing the circulation/kill procedure.

Abstract: A well completion system for reducing the pressure drop in fluids produced from a downhole formation ( 14 ) traversed by a wellbore ( 32 ) is disclosed. The well completion system comprises a production tubing ( 30 ) used to bring the formation fluids to the surface that is positioned within a well casing ( 34 ) that lines the wellbore ( 32 ). An expander member ( 56 ) is positioned within the production tubing ( 30 ) and travels longitudinally within the production tubing ( 30 ) to expand the flow area within the production tubing ( 30 ) once the production tubing ( 30 ) has been installed downhole, thereby reducing the pressure drop in fluids produced through the production tubing ( 30 ).

Abstract: A system and method for producing earth formation fluids such as crude oil using a lighter oil to force the crude oil to the surface and thereafter removing the lighter oil by gas lift techniques. The well system includes spaced packers defining a production chamber in the well bore, a production tubing extending through the packers having check valves and ports for well fluids to flow into the chamber from below the packer while isolating the chamber from the pressure of production fluids in the production tubing. Power fluid tubing extends through the upper packer into the production chamber including spaced gas lift valves and gas flow means from the lowermost gas lift valve into the production chamber. Surface equipment is provided for pumping power fluid into the power fluid tubing string, introducing lift gas into the power fluid tubing string above the upper packer, and separating returned power fluid and lift gas. In the method, formation fluids flow into the production chamber under formation pressure, power fluid is pumped into the chamber displacing the formation fluids through the producing string, and the power fluid is removed from the production chamber and power fluid tubing by lift gas.